Help With Api Tap Water Filter

[goawayou]

Hi, i just purchased the API Tap Water Filter to help me totally clean out my tap water because I have high phosphate issues.
However, after following the instructions to apply the supplied electro-right and PH adjuster and the proper amounts… I still get a PH that way off the scale too low. Before filtering the water, I had perfect 7.0 PH water.
I know that the filter will take out the sediments from the water necessary to get an accurate reading for PH… but how long does it take for the added adjusters to work? Or do I need to add more than what the bottles say?


Thanx for the help!

 

[waterdrop]

Not familiar with this.

There was someone on here a while back discussing some type of tap water filter but I can't recall where that thread was, sorry!

~~waterdrop~~

 

[Essjay]

There were actually three threads, but this one included the info in the others -

http/www.fishforums.net/index.php?showtopic=281521&hl=

Re-reading it, it seems the OP modified the filter, so I don't think they will be much help here! Although, if the problem here is high phosphates, I suppose the filter could be modified the same way using something to remove phosphate, if such a thing exists.

 

[waterdrop]

Amazing Essjay! You found exactly what I was thinking of...

 

[Anna Robinson]

The API Tapwater Filter simply produces pure deionized water. You therefore have to add back the hardness, and the buffering capacity.

If your pH is too low, then yes, I suppose you would need to add more pH adjuster. Is there any reason why it might be low? In theory if you add the amounts of Electro-Right and pH adjuster specified, it should give you the right conditions.

If you are happy with your tapwater's hardness and pH but not its phosphate, an alternative would be to simply use a phosphate-absorber.

 

[waterdrop]

What's the difference between a filter that does dionizing like this and an RO unit?

~~waterdrop~~

 

[Essjay]

Deionised water is made by passing the water through a resin that is electrically charged. Particles that have a charge will stick to the resin. Salts, when they are dissolved in water, separate into charged particles called ions, eg common salt is sodium chloride, which dissociates into positively charged sodium ions and negatively charged chloride ions. So these stick to the resin. Other ions will also stick - potassium, calcium, sulphate, nitrate etc etc. But impurities that don't have a charge won't stick, and they will remain in the DI water eg dust, bacteria and viruses.

Reverse osmosis - I'm not sure about that, as I've never seen one. My understanding is that pressure is used to push the water through a semipermeable membrane. That is one that allows the water to pass through it, but not anything dissolved in the water, and not larger particles either.

Presumably, the effectiveness of either method depends on the quality of the resin or membrane. I don't know how effficient they are in the equipment for use in the home.

Back in the dark ages when I was at university, we used deionised water as that was good enough for most chemical reactions. I've never used RO water, so I can't say much about it.

 

[OldMan47]

RO is a very easy to understand process. When a semipermeable membrane is placed in water with 2 different solutions on the two sides, the osmotic pressure will make the pure water want to move from the pure water side to the salty side, the side with impurities. If the system is just left to reach its own equilibrium, the side that started out salty will end up with a level higher than the side that started out pure water because of that osmotic pressure. The difference in height is measured and the resulting pressure difference is called osmotic pressure. An RO takes advantage of the fact that the osmotic pressures are fairly low and that if pressure is applied to the salty side, the process can be reversed. This means that if you take water that has impurities and put it on one side of a permeable membrane, the water can be forced through the semipermeable membrane in the wrong direction. The water will move through the membrane and leave the impure water behind. The water on the other side of the membrane will be much lower in dissolved solids that the water that you started with.
As Essjay said, the ion exchange resins work by a different principle. Positive ions in the form of H+ are used to regenerate cation resin and negative ions in the form of OH- ions are used to regenerate anion resin. When water with an ionic salt in it passes through a mixed bed of resin, the anions are swapped with OH ions and the cations are swapped with H ions. The result is that the ionic salt stays behind and the stuff coming out the other side of a mixed bed has H and OH ions that combine to form H2O. We call that salt made of H and OH water.

 

[waterdrop]

Thanks guys! WD